HOW DOES A FIREWALL WORK?

A firewall monitors incoming and outgoing network traffic and decides whether to allow or block the traffic. It uses a preset list of security rules to make decisions, and then it will establish a barrier between your internal network, which is secured, controlled and trusted, and the outside networks, such as the Internet. Using a firewall is the single most effective method for protecting your computer from becoming infected with viruses, worms and hackers.